Rename FABRIC series: FABRIC.md->0, FABRIC-2.md->1, FABRIC-3.md->2, FABRIC-4.md unchanged

FABRIC.md -> FABRIC-0.md
FABRIC-2.md -> FABRIC-1.md
FABRIC-3.md -> FABRIC-2.md (the current/living document)
FABRIC-4.md unchanged (new #3 to follow separately)

Every cross-reference repo-wide updated to match, including doc-comment
citations inside kernel source (.c/.h) files -- done via an ordered
placeholder substitution (FABRIC-3.md->placeholder2, FABRIC-2.md->
placeholder1, FABRIC.md->placeholder0, then placeholders resolved to
final names) in a single pass per file to avoid double-shifting
already-renamed references.

One line in capsules/font.4th grew past the 64-char block-format limit
as a side effect of the longer filename; shortened it and reverified
with mkcapsule --lint (34/34 pass) before rebuilding.

Verified 3-arch boot to ok> (amd64/aarch64/riscv64, each in the
foreground) after the fix; logs and DoE CSVs from this session's
verification runs included per this repo's own audit-artifact
convention.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var

include/starkernel/capsule_console.h

@@ -8,7 +8,7 @@
 */
 
 /**
- * capsule_console.h - Bare console-VM birth (FABRIC-3.md Phase F,
+ * capsule_console.h - Bare console-VM birth (FABRIC-2.md Phase F,
  * 2026-08-28): a minimal VM whose only job is loading
  * common:messaging.4th and being the physical REPL's relay target
  * (sk_repl_dispatch_line(), repl.c) for a paired user VM
@@ -35,7 +35,7 @@
  *                       "CaptBob"); sk_repl_dispatch_line() looks for a
  *                       live "<name>~user" counterpart to decide
  *                       whether a given active VM is a console.
- * @param parent         Who is birthing this VM (FABRIC-3.md §H.12 step 7)
+ * @param parent         Who is birthing this VM (FABRIC-2.md §H.12 step 7)
  *                       -- passed straight through to capsule_birth_baby().
  * @param out_vm_id      Output: assigned VM ID.
  * @param out_vm_ctx     Output: new VM context (may be NULL).